This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. To maintain their genetic integrity, eukaryotic cells must segregate their chromosomes properly to opposite poles during mitosis. Errors in this process give rise to aneuploidy that is implicated in cancer progression and birth defects. In mammals, Aurora B complex is responsible for detection and correction of faulty centromere/microtubules attachments. The aim of this project is to study the structure, function and regulation of the Ipl1 complex in yeast that is the equivalent of the Aurora B complex. Ipl1 complex downstream targets are pretty well known but the mechanisms responsible for its activation and localization are poorly understood, so I am focusing on upstream activation and localization of Ipl1 complex.